我国中部地区自动站与人工站气温的差异及原因分析

Causality of Temperature Differences Between AWS-and Manual Observations in Central Part of China

在我国,地面自动气象观测系统正在取代常规主要气象要素的观测,即人工观测的器测项目,新旧两种观测系统之间存在一定的差异。从气候科学的观点来看,这种差异会造成均一性数据集的开发以及极端天气事件的分析的误差甚至错误,所以将两种系统所获取的资料进行对比是非常必要的。计算了我国中部地区21个气象站2005年的年平均差值,对其中的6个国家基准气候站逐小时数据按照云量、风速、白天和黑夜进行分类对比,并将仪器所处环境、太阳辐射(夜间为辐射冷却)、仪器原理及观测方法的变化认为是气温差异产生的主要因素。研究表明:两种仪器观测的气温年平均差值基本上在±0.2℃之内。在上述差异因素中,大多数的台站仪器差异基本在±0.1℃之间,观测方法差异、仪器环境差异也比较小,而与太阳辐射有关的差异最大。

The Automated Surface Observing System is currently replacing conventional observa- tions in China. There are differences between the old and new measuring systems. From a climatological viewpoint, it probably causes the errors when developing the homogeneous datasets and investigating climatic change, and analyzing the extreme weather events. So it is necessary to compare the data from the two systems. By means of computing the annual average differences of 21 weather stations in the Central China in 2005, and sorting analysis hourly .data of 6 national climate stations according to cloud amount, wind speed, day and night, the differences in site characteristics, solar radiation（ IR cooling in night）, instrument system and observing practice are considered the main factors. It is showed that the annual average difference of temperature is almost within ±0.2℃. Among the above-mentioned four factors, the instrument bias plays a part role, about 0. 1℃ at most stations, the bias about local effect and observing practice are very little, but the bias of radiation is the largest.